In reaction systems utilizing microorganisms, such as a wastewater treatment system and a system by which pharmaceuticals are produced by use of microorganisms, microorganisms are either directly added to a reaction mixture system or immobilized through a immobilization technique. When microorganisms are directly added to a reaction mixture system, reaction efficiency becomes generally lower. Also, in cases where immobilized microorganisms are employed, a substrate solution is usually allowed to pass through the immobilized microorganism phase, where the following problems are noted: insufficient contact time between the substrate and the microorganisms, or when the contact time is prolonged to a sufficient level, reaction efficiency is reduced. Therefore, from the viewpoint of reaction efficiency, direct addition of immobilized microorganisms into a reaction mixture is desired.
However, when immobilized microorganisms are directly added to a reaction system, not only does solid-liquid separation become difficult after completion of reaction, but separation and recovery of a reaction product; i.e., the target product, also become difficult. This is because the reaction mixture contains not only the reaction product, but also the starting materials, medium components, etc. Moreover, reactions making use of microorganisms and antigen-antibody reactions cannot proceed endlessly even when starting materials are added continuously. Indeed, since the reaction is eventually saturated, maintaining high reaction efficiency is difficult.
Accordingly, an object of the present invention is to provide means for realizing a reaction field of high reaction efficiency and facilitating separation and recovery of reaction product.